Gear drive



E. F. SMALL June 24, 1947.

GEAR 1mm:

I Filed Aug. 25, 1944 3 Sheets-Sheet 1 June 24, 1947.

E. F. SMALL emnnnxvs F iled A 25, 1944 3 Sheets-Sheet 2 20 jrlverfior.

June 24, 1947.

r 5.. F. SMALL GEAR DRIVE Filed Aug. 25,1944 15 Sheets-Sheet 3 PatentedJune 24, 1947 GEAR DRIVE Edward F. Small, Newton, Mass., assignor toBird Machine Company, South Walpole, Mass., a corporation ofMassachusetts Application August 25, 1944, Serial No. 551,086

Claims.

1 This invention relates to an improved positivegeared drive forrotating two different elements of the same machine in the samedirection but at a differential speed of said two elements. Theinvention is particularly useful in connection with various types ofapparatus for treatment of materials. for example, centrifugal and.grinding apparatus. The invention is described in connection with acentrifuge having a high-speed rotating centrifugal drum and a rotatingconveyer therein between which elements there are potential power andenergy losses dependent upon the difference in relative speeds, and thecharacter and load of material being treated by the machine. The objectof the present invention is to minimize such losses by'the improveddevice, as hereinafter described, and which also presents various othersubstantial mechanical and operational advantages including reducedoverhun weight, fewer working parts, and improved support, balance, andreduced weight of rotating parts, including in combination with saiddevice a novel lubrication system-all directed to more efllcientperformance and easier operation and maintenance of the machine.

A preferred embodiment of the invention is 11- lustrated in the drawingswherein- Fig. 1 is a view, partly in side elevation and partly inlongitudinal cross-section, showing the drive as applied to a typicalcentrifuge;

Fig. 2 is a transverse cross-section taken on line 2-2 of Fig. 1 withcertain additional parts of the lubrication system being showntherebelow in elevation;

Fig. 3 is a horizontal cross-section of the drive taken on line 3-3 ofFig. 2;

Fig. 4 is a further vertical transverse cross-section taken on line 44of Fig. 1, and

Fig. 5 is an isometric view of the drive (with top portion of the gearhousing removed) having certain parts broken away for clarity.

Referring to the drawings, in which like numerals represent like parts,and particularly to Fig. 1 thereof, the drive, generally designated 2,is connected to and supported by the flange 3 of a hollow drivin shaft 4and drum shaft 5, conwithin the central bearing portion a of the flangedmember 20, which is, in turn, afflxed as by studs 2| and nuts 22 to thesupporting and driving flange 3 of the hollow-driving shaft 4,

as shown. It will be seen from Fig. 1 that the flanged member 20 thuscarries (through the members 3, 4 and 5), cantilever fashion, all movingparts of the drive beginning with the cage l8 and its wing portions l8a,which carry, rotatably mounted therein, the two pinion-gear shafts 24,the gear pinions of which mesh with the internal gear 26 affixed to theradially extending flanged member 20, as by cap screws 21 (shown inFigs. 1 and 3). To the right-hand end of each pinion-gear shaft 24 iskeyed (as shown) for rotation therewith a flanged gear-carrying member28 rotatably mounted within bearing shells "lb of the two wings Wecarried by the gear cage extension l1 (Figs. 1 and 5) which is afllxedby nected to a rotatable centrifuge drum 6 mounted in supportingbearings 8 and 9 through the latter of which projects a hollow shaft illby which the centrifuge is internally supplied with fluid material to'be treated therein (the material exits not being shown). In effect, themembers 3. 4 and 5 function as though in one piece. Within the drum 6 isa conveyer member [2, carried within and mounted for rotation withrespect thereto, as shown in Fig. l.

The internal shaft H, by which the conveyer i2 is rotated, extends tothe right where it isconnected by a short, externally-splined stubshaftii to a gear cage l8 rotatably mounted dowels and cap screws l9 to androtated by the cage [8 as if said cage extension ll were an integralpart of the cage l8. Aflixed to the flange of each rotatably mountedmember 28 is a gear 30, each gear 30 meshing with a normally fixedcentral pinion-gear and shaft 32 carried in roller bearings 34 and 36,respectively, the shaft 32 extending to the right (Fig. 1) through astuffingbox bearing 38 mounted in the horizontally, longitudinally-splitstationary gear housing made up of a lower half 39 and an upper half 40,both provided with a labyrinth (as shown in Figs. 1 and 3) to preventthe escape of oil and the ingress of foreign matter from around therotating periphcry of the flanged member 20.

The right-hand end of the shaft 32 (Fig. 1) is normally held in fixed(non-rotating) position to the housing or elsewhere, by any suitablemeans, for example, by an externally held looking member 42 (not fullyshown) with a suitable, easily sheared key or pin connection with theshaft 32 as a safety feature. From the foregoing, it will be seen thatthe cage I8 and flanged member 20 carrying its internal gear member 26rotate about the common axis so as to provide a gear reduction betweenthe drum-driving shaft 4 and the conveyer-driving shaft l4, power beingapplied to the shaft 4 by silent chain or belt drive means (not shown)through toothed sprocket members or sheaves 4a keyed to the shaft 4(Fig. 1).

It will also be seen from the foregoing that the rotating parts in sizeand number have been cut to the minimum by way of reducing loads in bothdriving and accelerating the same, and that the rotating parts are allsuch as to be readily susceptible of accurate manufacture and balancing,all conducive to smooth running with minimum amount of vibration andpower absorbed.

The lubrication of the drive may be accomplished by a. built-in combinedsplash and circu- 3 latory system as shown so that all rotating parts ofthe drive receive oil through said system which embodies a sump 39a(Fig. 2) in which a quantity of oil is maintained at a suitable minimumlevel, being drawn from the sump through a combined oil storage tank (ofsubstantial capacity) and oil cooler unit 44 by a conventionalgear-oii-pump 48 from which the oil is forced through the feed pipe 41,as shown in Fig. 2, and fed to a channel 38b within and near the upperportion of the housing 39. The channel 38b thus receives oil from thepipe 41 and also catches and conducts oil splashed onto the inside wallsof the upper half 40 of the gear drive housing and thus, with or withoutthe oil fed through the feed line 41, supplies oil through the shortpipe 380 leading from the channel 35b into the rotating righthand end ofthe cage i8 where it is retained at a suitable level in an annularchannel i8d by an annular lip with short transverse members dividing thechannel into separate compartments, as shown in Figs. 1 and 3, the oilbeing held therein by centrifugal force due to the rotation of the cagei8. An oil-pressure head, for example, of the order of 15-20/p. s. 1.,may be provided in the device as shown when rotated say at 1400 R. P.M., affording ample oil pressure for lubrication. Oil under suchsuitable pressure is thus separately supplied from one of saidcompartments to each one of the two channels lie and, in turn, to thebearings l8b at the right-hand end of the cage l8 (Fig. 1) and is fed tothe bearings of the two pinion-gear shafts 24 at the opposite end of thecage l8 through separate channels "I extending from the respectivecompartments of the annular channel [8d (see Fig. 3) to a second annularchannel l8g wherein the oil is likewise held at a suitable level by alip, as shown, the oil being fed from said channel l8g through radiallyextending oil passages N72 to the respective left-hand ends or bearings(Fig. l) of the shafts It. The separate compartments and oil passagesleading therefrom, respectively, thus insure a more nearly uniform feedof oil to the respective bearings and gears. Oil is also directlysupplied to the pinion-gears of the shaft 24 from the channel I80through the passages l8i, as shown in Fig. 1.

In addition, oil may be supplied to the roller bearings 3| and 36mounted to the shaft 32 through the hollowbore of shaft 32 with radialholes opposite the respective bearings 34 and 36 into which bore the oilis fed by gravity from an overhanging lip 4| (Fig. l) on the upper halfof the stationary housing, the oil being fed from said lip to the hollowbore through a radial hole in the normally fixed shaft 32.

It will be seen from the foregoing that the device will function bysplash (due to gears 30 swinging through the oil sump 39a) to adequatelylubricate all bearings of the drive with or without the operation of thepump 48, thus providing a safety factor for possible oil pump failure.Also, the oil pressure is the same at the normal operating speed whetheror not the oil pump functions due to the centrifugal oil-pressurefeature of the rotating gear cage.

It will also be evident from the structure of the drawings that theoverhung, i. e. cantilever-supported, weight of the drive is muchreduced by the provision of the horizontally-split stationary gearhousing and that there is no difllculty in oil retention since thehousing itself is not under oil pressure, but, instead, simply serves tocontain oil thrown from the gearing and return it to the centrifugaloil-pressure system. Furthermore,

the split housing facilitates inspection, cleaning, and propermechanical maintenance oi. the gearing by simply removal of the top halfthereof, as well as providing a guard for the moving parts preventingcontact with and/or possible failure and escape of parts or fragmentsdue to centrifugal force at high speed rotation, commonly of the orderof 1000 to 2000 R. P. M.

In accordance with the above description, it will be appreciated bythose skilled in the art that I have provided a novel, improved, thoughsimple, drive for rotating apparatus, for example, centrifuges, and thatsaid drive when properly dynamically balanced, will afford highlyefficient and trouble-free operation for the purpose intended.

Having described my invention, I claim:

1. A device of the class described, having in combination two concentricshaft elements one outside the other adapted and connected to be drivenat different speeds from a single source of power directly applied tothe outer one only of said elements, a gear cage wholly supported by androtatably mounted upon one of said elements but connected to rotatedirectly the other of said elements, pinion-gear stub shafts carried bysaid gear cage in parallel relation to but spaced from the common axisof said concentric shaft elements so as to rotate bodily in an orbit,and gearing means connecting said stub shafts and the other of saidelements, each of said stub shafts being geared to a central fixedshaft.

2. A device of the class described, having in combination two concentricshaft elements, one outside the other adapted and connected to be drivenat different speeds from a common source of power directly applied tothe outer one only of said elements, a gear cage wholly supported fromand geared to one of said elements but directly connected to rotatedirectly the other of said elements, pinion-gear stub shafts carried bysaid gear cage in parallel relation to but spaced from the common axisof said concentric shaft elements so as to rotate bodily in an orbit andprovide the gearing connection with said element supporting said cage,and gears affixed to and carried by said stub shafts, a central normallyfixed shaft having a pinion-gear meshing with each of said gears carriedby said stub shafts.

3. A device of the class described, naving in combination two concentricshaft elements, one outside the other adapted and connected to be drivenat different speeds from a single source of power directly applied tothe outer one only of said elements, a gear cage supported from andpositively geared to an internal gear carried by one of said elementsbut directly connected to rotate directly the other of said elements,piniongear stub shafts carried by said gear cage in parallel relation tobut spaced from the common axis of said concentric shaft elements so asto rotate bodily in an orbit with each of said piniongears meshing withsaid internal gear, a central normally fixed shaft, and gearing meansconnecting said stub shafts and said normally fixed shaft.

4. A device of the class described, having in combination two concentricshaft elements one outside the other adapted and connected to be drivenat different speeds from a single source of power directly applied tothe outer one only of said elements, a gear cage directly connected torotate directly one of said elements but wholly supported by the otherof said elements, piniongear stub shafts carried by said gear cage inparallel relation to but spaced from thecommon axis of said concentricshaft elements so as to rotate bodily in an orbit, gearing meansconnecting said stub shafts and the other of said elements, each of saidstub shafts being geared to a central fixed shaft axially aligned withsaid concentric shaft elements, and an oil-tight independently supportedstationary housing for said gear cage, stub shafts and gearing means.

5. A device of the class described, having in combination two concentricshaft elements one outside the other adapted and connected to be drivenat different speeds from a single source of power directly applied tothe outer one only of said elements, a gear cage wholly supported by oneof said elements but connected to rotate directly the other of saidelements, pinion-gear stub shafts carried by said gear cage in parallelrelation to but spaced from the common axis of said concentric shaftelements so as to rotate bodily in an orbit, gearing means connectingsaid stub shafts and the other of said elements, each of said stubshafts being geared to a central,

fixed-shaft, and an oil-tight stationary housing for said gear cage,stub shafts and gearing means.

6. A device of the class described, having in combination two concentricshaft elements one outside the other adapted and connected to be drivenat different speeds froma common source of power directly applied to theouter one only of said elements, a gear cage supported from and gearedto one of said elements but directly connected to rotate directly theother of said elements, pinion-gear stub shafts carried by said gearcage in parallel relation tobut spaced from a the common axis of saidconcentric shaft elements so as to rotate bodily in an orbit and providethe gearing connection with said element supporting said cage, gearsaffixed to and carried by said stub shafts, a central normally fixedshaft having a pinion-gear meshing with each of said gears carried bysaid stub shafts, and an oil-tight independently supported stationaryhousing for said gear cage, stub shafts and gearing means.

7. A device of the class described, having in combination two concentricshaft elements one outside the other adapted and connected to be drivenat different speeds from a single source of power directly applied tothe outer one only of said elements, a gear cage positively geared to aninternal gear carried by one of said elements but directly connected torotate directly the other of said elements, pinion-gear stub shaftscarried by said gear cage in parallel relation to but spaced from thecommon axis of said concentric shaft elements so as to rotate bodily inan orbit with each of said pinion-gears meshing with said internal gear,a central normally fixed shaft, gearing means connecting said stub shaftand said normally fixed shaft, and an oiltight independently supportedstationary housing for said gear cage, stub shafts and gearing means.

8. A device of the class described, having in combination two concentricshaft elements one outside the other adapted and connected to be drivenat different speeds from a single source of power directly applied tothe outer one only of said elements, a gear cage supported from andpositively geared to an internal gear carried by one of said elementsbut directly connect. to

rotate directly the other of said elements, piniongear stub shaftscarried by said gear cage in parallel relation to but spaced from thecommon axis of said concentric shaft elements so as to rotate bodily inan orbit with each of said piniongears meshing with said internal gear,a central normallyfixed shaft, gearing means connecting said stub shaftsand said normally fixed shaft, and an oil-tight independently supportedstationary housing for said gear cage, stub shafts and gearing means.

9. A device of the class described, having in combination two concentricshaft elements adapted and connected to be driven at different speedsfrom a single source of power directly applied to one only of saidelements, a gear cage directly connected to rotate with one of saidelements, said gear cage having an internal channel for receiving oiland holding oil therein by centrifugal force and means' to supply oil tosaid channel, pinion-gear stub shafts carried by said gear cage inparallel relation to but spaced from the common axis of said concentricshaft elements so as to rotate bodily in an orbit, gearing meansconnecting said stub shafts and the other of said elements, each of saidstub shafts being geared to a central fixed shaft axially aligned withsaid concentric shaft elements, an oil-tight stationary housing for saidgear cage, stub shafts and gearing means, and conduits supplying oilunder pressure from said channel to said stub shafts and gearing means.v

10. A device of the class described, having in combination twoconcentric shaft elements adapted and connected to be driven atdifferent speeds from a single source of power directly applied to oneonly of said elements, a gear cage supported by one of said elements butconnected to rotate with the other of said elements, said gear cagehaving an internal channel for receiving oil and holding oil therein bycentrifugal force and means to supply oil to said channel,

pinion-gear stub shafts carriedby said gear cage in parallel relation tobut spaced from the common axis of said concentric shaft elements so asto rotate bodily in an orbit, gearing means connecting said stub shaftsand the other of said elements, each of said stub shafts being geared-toa central fixed shaft, an oil-tight stationary housing for said gearcage, stub shafts and gearing means, and conduits supplying oil underpressure from said channel to said stub shafts and gearing means. i

- EDWARD I". SMALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS.

